import json

try:
    a="Hello, UDP Echo !"
    b=json.loads(a)
    print(b)
    #定位 字典数组
    print(b['resp']['focus_status'])
except Exception as e:
    print("非json字符串:",e)

# 运行结果:
# 非json字符串: Expecting value: line 1 column 1 (char 0)